Unsure about this one, there is a lot of people who say for stuff like cancer a full cannabis oil Inc THC is the best bet (Google RSO oil etc) but as that's probably not something we can talk about I'll leave that there.
If going down the CBD route I would go for oral tinctures mainly and perhaps the vape as top up dosage.
I believe CBD brothers rib mentions are one of the 'good guys' in a market full of fraudsters but I've not tried their capsules.
I can vouch for one vendor who do very good quality tinctures at a good price, not sure in the rules mentioning companies but their well known and I'm in no way affiliated just ping me a pm if you want their website
Either way good luck